We consider the canonical problem of Boussinesq convection in a sphere of radius \(r_o\) , which rotates at \(\Omega =\Omega {\hat{z}}\) . Convection is driven by a uniform heat source \(S\)  under a gravitational field \(g=-g_or/r_o\) . The problem was first formulated by [1]} and is governed by the following dimensionless equations in the rotating frame:
\( E \left(\frac{ \partial u}{\partial t}+{u\cdot \nabla u}\right)+{\hat{z}}\times u=-\nabla p +\frac{ERa}{Pr}Tr+E\nabla ^2 u,\) 
\(Pr \left(\frac{ \partial T}{\partial t}+{u\cdot \nabla } T \right)=\nabla ^2 (T-T_b),\) 
\( {\nabla \cdot u}=0,\) 
